seperis

Select, Edit-> Stroke. Make sure you only have anti-aliasing on (in selection) if you want to.

Having fun at work?

well you can just draw it on a layer with teh ractangle tool and then choose Stroke in the umm.. layer menu?
http://www.neoblonde.com/extra/lj/tutorial/Clipboard_01.jpg
http://www.neoblonde.com/extra/lj/tutorial/Clipboard_02.jpg

Or do a rectangle with the multiple geometric shape tool and then just choose Fill 0% and then rightclick and change the style with "Blending options"

http://www.neoblonde.com/extra/lj/tutorial/Clipboard_03.jpg
http://www.neoblonde.com/extra/lj/tutorial/Clipboard_04.jpg

Use your selection tool (Rectangular Marquee Tool) to draw the box, then go up to Edit, scroll down to Stroke, select width and color of the line, hit Enter. That ought to do it. If you do it in a new layer, you can go back and move the box around using the Move Tool.

There are many ways to do that, but this is what I do usually:
1. Create new layer on top of your original picture
2. With rectangular marquee tool, select the area that will framed by the lines (if you want square, press shift key while doing it)
3. Inverse selection by select > inverse (now you can see selected rectangle or square frames)
4. Color the selected frame by paint bucket tool (You can do pretty much anything you want in this way, since its layer)

If you just want a 1 px outline, you can do this:

1) make a new layer
2) use the rectangle or circle tool to form the shape you want
3) set the FILL, not the opacity to 0
4) right-click on the layer and go to blend properties or whatever it's called
5) click 'stroke' and twiddle with the settings.

this way, even if you want to change the shape, you just have to clear the shape you drew and redraw a new shape.

Uh, easiest way is probably this... Oh, and please forgive my use of capslock; I'm just attempting to make the instructions clearer because I don't know how much Photoshop experience you have.

Create a new layer.

Now, find your CUSTOM SHAPE TOOL. It may be under your LINE TOOL. It looks like a blobby star.

When you have selected your CUSTOM SHAPE TOOL go up to the tool option thingy that should be right below the menu bar (file, edit, etcetera). It will have pictures of the SHAPE TOOLS on it. The CUSTOM SHAPE TOOL's picture should still be selected, and next to it is a dropdown-arrow.

Hit the dropdown arrow. Make sure you have UNCONSTRAINED selected and that nothing else is selected. This gives you more maneuverability in the next step.

Now, to the RIGHT of that dropdown arrow is either a picture of a right-pointing arrow with a dropdwon arrow next to it, or another picture. This is where you pick your CUSTOM SHAPE. Click on the dropdown arrow. Scroll through the options that come up.

There is one called the SQUARE THIN SHAPE. In the list, it looks like a white box with a black edge. SELECT THAT ONE.

Now, still in the tool options, further to the right of the CUSTOM SHAPE selection list thing, there should be an option for what COLOR you want your custom shape to be. SELECT YOUR COLOR.

Now, go to your picture. Click and drag, and the box will appear. Make it a size to suit. It will be a "hollow" frame around whatever you're making a box around.

Also, because you drew the CUSTOM SHAPE on a new layer, you can make sure that layer is selected in your LAYERS box, and use the MOVE TOOL (which looks like a cursor arrow with a tiny compass next to it) to move the layer around above your object.

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If this is not what you meant, I know lots of other ways to accomplish a "border box" or "frame" or "lines" around objects.

Or you could right click on the layer (if you don't have it locked), go to blending options and go to Stroke. That is, if you want to outline an entire picture. If you marque, copy and past to a new layer you can do the same thing. You can also do all sorts of cool things with the blending options like drop shadow and emboss.